Utilização de extratos naturais na produção de papel indicador ácido-base como ferramenta para aulas práticas de química básica.

Abstract

Acid-base indicators or pH indicators are organic substances weakly acidic or weakly basic feature different colors in their protonated and deprotonated forms. Typically, the pH indicators are natural pigments extracted from plants and dissolved in water, present certain color. Thus, the purpose of this study was to identify the species that serve as an indicator of pH in the Curimatau region of Paraiba, extract the pigments these plants and develop a pH indicator paper, using the methods involved to propose tools in practical classes which will support basic chemistry classes. For this, four regional species were identified, which were collected in the region and soon after he was made the same dye extraction by maceration in ethyl alcohol. We studied different colors presented by various natural indicators showing change of color in acidic, medium acidity, neutral, medium basic and basic, which was obtained with indicator papers efficient response comparable to commercially available, with the advantage have a low cost and easy to obtain. In the process of obtaining the pH indicator paper at each stage of the process can be turned into a teaching tool riding routes practical classes where you can be involved various contents related to chemistry and even other disciplines. The use of plants as a pH indicator offers students a direct contact chemistry using an object and present attractive in their day-to-day.